This invention relates to optical instruments and more particularly to an optical instrument designed to measure the color of a surface by measuring the diffuse reflectivity of the surface at different wavelengths throughout the visible spectrum and also to measure the gloss of the surface by measuring the specular reflectivity of the surface at a predetermined angle.
Color measurement of a surface is conventionally carried out by irradiating the surface and detecting the light diffusely reflected from the surface at different wavelengths throughout the visual spectrum. However, color perception is greatly affected by the gloss of the surface, that is the degree to which the surface reflects light specularly. Accordingly, there is a need for an optical instrument which will conveniently make color measurements on the diffusely reflected light from the surface as well as the specular reflectivity of the surface at the same place on that surface. The present invention provides an optical instrument which measures the color of a surface by spectroscopically measuring diffusely reflected light from the surface and which also measures the gloss of the surface by detecting light specularly reflected from the surface.